When evaluating a prefab house kit, prioritize the structural frame material, typically Light Gauge Steel (LGS) or galvanized steel Q235/Q345, for its anti-corrosive properties and seismic resistance. Ensure the wall panels (such as EPS, Rockwool, or PU sandwich panels) provide a density of at least 12kg/m³ for adequate thermal insulation and soundproofing. Additionally, verify that the floor load capacity meets residential standards, usually ≥2.0kN/m², to ensure safety for a 3-bedroom family layout.